SqlParameter mPLType = new SqlParameter("@pltype", pPLType);
SqlParameter mOrderIndex = new SqlParameter("@orderindex", pOrderIndex);
FillByStoredProcedure("spx_GetOrderItemList", mPLType, mOrderIndex);

It did not work...well, I didn't think it did.  It's a good thing to set the DataSourceKey on the BO, too.    It tends to misbehave when that is missing.  Once I put that back in, then both your code and my code works just fine.  Sorry for the oversight. 

Thanks for helping!
Bill